Telephone-exchange system



C. WHITE. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JULY n, 1918.

1,3863%? 0 Patented Aug. 9, 1921.,

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CHARLES WHITE, OF ORANGE, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, NEW YORK, N. Y., A CORPORATION OF NEW YORK.

IELEPHON E-EXGHAN GE SYSTEM.

' Application filed July 11,

T 0 all 10 from it may concern Be it known that I, CHARLES harm, a citizen of the United States, residin at East Orange, in the county of Essex, tate of New Jersey, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems and more particularly to such systems in which trunk circuits are employed. I

In systems of this nature in which the same trunk circuit is employed for different classes of service, it is desirable to provide signaling means to positively indicate the class of service with which the trunk circuit is to be associated in a particular instance.

It is the object of the present invention to provide an improved system of this character which is simple and inexpensive and provides signaling means for certain classes of service which are unafiected by the operation of the signaling means for the other classes of service or by incidental features encountered in the operation of the system. Y To attain this object in accordance with a feature of this invention, a trunk circuit local connection from posltion X to position arranged for plural service and reciprocal operation and provided with two; signal co11- trol means responsive to signaling currents of different characteristicsis provided with means responsive to the operation of one of the signal control 'means'for rendering the other ineffective while the trunk is being used for the selected service.

In accordance with another feature of the invention, such a trunk circuit is provided with means also responsiveto the operation of the selected signal control means to discharge the capacitance retained in the trunk circuit after the selected signaling current has been removed, thereby preventing the i false operation of the other signal control means when it isassociated with the trunk circuit upon the disengagementof the trunk the invention, together, with sufficient-portions of suitable connecting circuits for the Specification of Letters Patent.

Patented Aug. 9, 1921.

1918. Serial No. 244,360.

different classes of service to properly illustrate the invention.

In the drawings the switchboards, operators positions or stations-X and Y are joined bythe trunk circuit A terminating at position X in jacks 2 and 14 and at position Y in jacks 102 and 114. Associated with jacks 2 and 14 are calling signal lamps 18 and .26 respectively and associated with jacks 102 and 114 are calling signal lamps 118 and 126 respectively. Jacks 2 and 102 are adapted for use in connection with one class of service such as local calls, while jacks 14 and 114 are adapted for use in connection with another class of service such as toll calls. At station X suitable connecting circuits B' and C are provided for use with jacks 2'and 14 respectively and at station Y similar connecting circuits D and E are provided for use with jacks 102 and 114 respectively, only suflicient portions of each con-' necting circuit being shown to properly illustrate the invention.

It is believed that the invention may be Y, the operator at position X inserts the calling plug 1 of link circuitB into the ack 2 of the trunk circuit A. Supervisory lamp 4 is lighted and relay 7 is operated over a circuit established from battery through lamp 4, resistance 3, sleeve contacts of plug 1 and jack 2, lower normal contact of relay 8, lower normal contact of relay 9 and winding of relay? to ground. The closure of the upper contact of relay 7 short-circuits the left hand high resistance winding of relay 10, while the closure of the lower contact of relay 7 causes the operation of relay 11 over a circuit extending from battery throughthe winding of relay 11, the lower normal contact'of relay 12, the upper normal contact of relay 13 and the lower contact of relay"? to ground. Relay 11 is thereupon looked over a circuit extending from battery, through the winding and lower outer alternatecontact of relay 11 and the lower contact of relay 7 to ground. Relay 13 is also operated over a circuit extending from battery through the upper winding of relay 13,

the upper. outer alternate contact of relay relay ,7 to ground.

11, and the lower contact of relay 7 to ground. Relay 13 is thereupon locked over a circuit extending from battery, through the upper winding and middle alternate contact of relay 13, and the lower contact of upper alternate contact of relay 13, a busy test potential is connected to the sleeve con; tact of ack'l4e through resistance 15 and the upper alternate contact of relay 13., The operation of relay 11 operates relay 110 at position Y over a circuit extending from battery, through resistance 16, the upper inner alternate contact of relay 11, the upper contact of relay 7, the left-hand low resist ance winding of relay 10, the upper normal contact of relay 9, the middle normal contact of relay 8, the ring conductorfof the trunk circuit,- the middle normal contact of relay 108, the upper normal contact of relay upper and lower normal contacts of relay 111, the. upper normal contact of relay 108, the tip conductor of the trunk circuit and the lower inner alternate contactof relay 11 to ground. Relay 10 does not receive suiiicientcurrenttto cause its operation at thisptime, but relay 1:10 is operated, efi'ecting the operationof relay' 112 over a circuit eX- tending from battery, through the winding of relay112and theficontact of relay 110 to ground. By the closure of its upper outer alternate contact, relay 112 extends the con.

tinuity of the conductor-associated with the ringcontact o fjac'k 102, while-bythe closure of. its upper inner alternate contact lamp 118 is'lighted over acircuit-extendingfrom battery, through the-lower normal contact 7 of relay 113, the upper inneralternat e 'contact of relay 112 and the lamp 118 to; ground.

The closure of the lower outer alternate con'- tact of relay 112 connects a busytest potential to-the sleevecontact of jack 1'14: throiligh resistance 115,'and the lower alternateicon= tact of relay '112.

" illumination of lamp-118inserts plugflOl of link circuit D into the jack 102, thereby" operating supervisory relay 106 over a circuit extending from battery, through the winding of'relay'106, the ring, contacts of plug 2 1.. 101 and jack 102;,the upper outer alternate contact of relay 112, resistance 119 and the.

tip *contacts of jack 102 and plug .101 to ground. Supervisory'lamp 104 is thereupon the, contact of relay 106,1 resistance 105 and 103, the sleeve contacts of plug 101 and jack 102, the lower normal'contactj of relay 108, thexlower normal contact of relay 109,

and the winding of relay 107 to ground.

The closure of the upper contact of relay,

107 short-circuits the left-hand high resist- By theclosure of the,

battery, through the upper winding of relay 1 13, the lower inner alternate contact of The operator'at station ,Y observing the low resistance winding of relay 1 0 suflicientlyto permit its operation atfthis tlme.

Upon the actuation of relay 107, relay 113 is operated over a circuit extending from through the winding orre1a ;12 and the contact of relay 10 to; ground and locks res lay '18,.over a circuit extending from battery, through the lower alternate contact tact of relay 10 to ground. Lamp 18 is not lighted due to the openingofthe lower normalcontact of relay 13. lnoperating, relay 12' extends the continuity of the conductor thereby operating supervisory relay =6 over the winding of relayfi, the ring contacts of; plug-1 and jack v 2', the upper o'uter' alternate contacts "or" ack 2 and plug 1 to; ground.

Lamp'is thereupon sht'mted-by the resistauce 5 and thereby .extilwuished,"notifying the operator at position kthat the operator in'g circuit igs' thereupon completed over the.

conductors;ofthe trunk circuit so that a subscriber whoseline isassociated with-link circuit B at position X m ay;conversewith with link circuitD-at station Upon the completion of the conversation, the operator-at position-X removes the plug and lower winding of relay. 1'3and the con- 5:;

connected to the ring contact of jack" 2,

a circuit extending from battery, through V contact of relay;12, resistance 19-and theltip at position Yhaslaneweredthe call. A talk- 2:;

ll 0 another-subscriber? whose lineiis' associated a 1 from the ac-lr2, releasingrelay 7 to remove 11 the short; circuit aroundthe left hand. high resistance. windingof-relay 10. andlthereby,

increasing.thearesistance ii -circuit with relay.- suffic ently to'fcause its-release, Relay,-

112 thereupon releases to open-the Conductor j connected. togthe ring contact o'f'ja'ck 102: caus ngthe. release of relay 106,;which re moves the resistance 105 from its shunt 'relat1onw1thjlamp104 and causesthe l ghting of such lamp over a circuit extending from bat- 1 5 tery,.throughlamplOa, resistance 103, the sleeve contacts-of plug 101, and aclr102, the lower normal contact. of relay 108,. the'lower normal contact of relay109, and the winding of relay 107 to ground. pen the subsequent disconnection of link circuit D, all apparatus returns to normal.

In case the local call originates at position Y, upon the insertion of the plug 101 into the jack 102, supervisory lamp 104 is lighted,

relays, 107, 111, 11.3, 10 and 12 are operated, relay 113 is locked, calling signal lamp 18 is lighted, a busy potential is connected to the sleeve contacts of jacks 114 and 14 and the break in the ring conductor is closed as previously described in connection with lamps 4 and 118, relays 7, 11, 13, 110 and 112, and jacks 14 and 114. Upon the insertion of plug 1 into the ack 2, in answering the call, relays 106, 107, 110, 13 are operated, relay 13 is locked, lamp 104 is shunted by resistance 105 and thereby extinguished, lamp 18 is extinguished, a break in the ring conductor'associated with jackl02 is closed to complete the circuit for relay 106, including resistance 119 as previously described for relays 107, 10, 113 and"6,'la1nps 4 and 118, resistances 5 and 19 and jack 2. Upon the disconnection of the plug 101 from the jack 102, relays 107, 10, 12

and 6 release, the break and the ring conductor. associated with ack 2 is opened, the resistance 5 is removed from its'shunt relation with the lamp 4, which is thereby lighted, as previously described for relays .7, 110,

112 and 106, jack 102, resistance 105 and lamp 104. Upon the subsequent disconnection of plug 1 from jack 2 all apparatus returns to normal. i

In case it is desired to extend a toll call from position X to position Y, the operator at position X inserts the plug 20 of a link circuit G into the ack 14, thereby operating relay 22 over a circuit extending from bat tery,'through resistance 21, the sleeve contacts of plug 20 and jack 14, and the winding of relay 22 to ground. Relay 8 is thereby operated over a circuit established from battery, throughthe lower normal contact of relay 13, the upper normal contact of relay 12, the winding of relay 8 and the alternate contact ofrelay 22 to ground. By opening its upper and middle normal contacts relay 8 removes the ti and ring conductors of the trunk circuit ro'm their normal association with the local ack 2 and by closing its upper outer and lower inner alternate contacts connect's such conductors to the .tip and ring contacts respectively of the toll ack 14. A busy test potential is also connected to the sleeve contact of jack 2, through resistance 15 and the upper inner alternate contact of relay 8. The operator at position X actuates the ringing key 24 to connect a source of signaling current to the trunk circuit, thereby operating relay 123 over a circuit extending from the source of signaling current, through the lower alternate contact of ringlng key 24, the ring contacts of plug 20 and jack 14, the lower inner alternate contact of relay-8, the ring conductor of the trunk circuit, the middle normal contact of relay 108, the condenser 125, the winding of relay 123, the upper normal contact of relay 108, the tip conductor of the trunk circuit, the upper alternate contact of relay 8, the tip contacts o1 jack 14 and plug 20 and the upper alternate contact of ringing key 24 to ground. Relay 109 is thereupon operated over a circuit established from battery, through the lower normal contact 01 relay 113,'the upper normal contact of relay 112, the contact of relay 123, the winding of relay 109 and the normal contact of relay 122 to ground. Relay 109 thereupon locks over a circuit extending from battery, through the lower nor mal contact of relay 113, the upper normal contact of relay 112, the middle alternate contact and winding of relay 109 and the normal contact of relay 122 to ground. Lamp 126 is lighted over a circuit extending from battery, through the lower normal contact of relay 113, the upper normal contact of relay 112, the middle alternate contact of relay l09,-and the lamp 126 to ground. A busy test potential is also connected to the sleeve contact of jack 102 through resist ance 115, the lower alternate contact of relay 109 and the lower normal contact of relay 108. By the opening of the upper normal contact of relay 109, the left-handwinding of relay 110 is disconnected from its normal association with the ring conductor of the trunk circuit and the slow operating relay 110 is thereby rendered unresponsive during the continued operationof relay 109. The closure of the upper alternate contact of relay 109 forms a shunt'path through resistance 127 and the'up'per alternate contact of relay 109, around condenser 128, serving to discharge the residual charge retained-by such condenser from the application of the signaling current. i

In answering the callfthe operator at position Y inserts the plug 120 of thelink circuit Einto the jack 114,,thereby operating relay 122 over a circuit extending from battery, through resistance 121, sleeve'contacts of plug 120 and jack 114 and the winding otrelay 122to ground. Relay 109'is re-, leased, extinguishing the lamp 126. Relay 108 is thereupon operated "over a circuit from battery, through the lower normal contact of relay 113, the upper normal contact of relay 112, the winding of relay 108 and the alternate contact of relay 122 to ground. The opening of the upper andmiddle normal contacts of relay 108 removes the tip and ring conductors respectivelyof the trunk circuit from. their normal association with the tip and ring contacts of jack'102, while the closureof the upper and lower alternate contacts o'f'relay 108 con nects such conductors to the tip and ring conductors respectively of jack .114. The closure or" the middle alternate contact of relay 108 serves to maintain a busy test potential connected to the sleeve contact of jack 102 through resistance 115 and the.

middle alternate contact of relay 108. As

' in the former case, a talking circuit is thereuponcompleted over the conductors of the trunk circuit so that a subscriber WhOSGllIlG isassociated with link circuit C at position tact of relay 8, the ring conductor of the. trunk circuit, the lower alternate contactv of .relay 108, the ring contacts of jack 114 V and plug 120, the lower normal contact of key 124, the winding of relay 129, the upper normal contact of key 124, the tip contacts of plug 120 and jack 114, the upper alternate contact of relay 108, the tip conductor of the trunkcircuit, the upper; alternate contact of relay'8, the tip contacts of jack 14 and plug 20 and the upper alternate con tact ofkey 24 to ground. Supervisory lamp 130 is thereby lighted over a circuit ex tending from battery, through thelamp 130 and the contact of relay 129 to ground. In response tothe illumination of the lamp 180,

y the operator at position Y removes the plug- 120 from the jack 1 14 and the operator at position X also removes the plug 20 from the jack 14, thereby permitting all appa 'ratus to return to normal. V In case the toll call; is originated at POSI- tion Y, the insertion ofthe plug 120 into "the jack 114 causes the operationof relays 122 and 108 overcircuits similar to those described for relays 22 and 8, thereby re} moving the trunk conductors from their normalv association with jack 102' and plac ing the busy test potential onthe sleeve contact of suchfjackin a manner similar to' that previously described in connection with. jack 2., Upon the actuation ofringingkey f 124, relay 23 is. operated causing the'sube sequent operation andlockingof relay 9,

the removal of relay from its. association with the ring conductor of the trunk circuit, the. discharge of condenser 28 through ashunt path including the resistance 27 and: the lighting. of lamp 26' as previously described for relays 128, 109, 110, condenser 1 28, r'esistance,12? and,lamp 126. In answeringthe call, the insertion of plug 'into jack l4 causes-the operationofrelays. 22and 8, therebvremoving the/trunk. cons. ductor-s from their normal'associationjwitli jack- 2, maintainingfa busy test potential connectedto the sleeve of such jack, releas ing relay 9 and extinguishing lamp 26, as previously described in connection with relays 122,108, and 109, jack 102.and lamp 126. AQ talking. circuit is also established similar to that otthe preceding case, en-- abling the subscribers whose lines areassociated with the link circuits and E respectively to converse, Upon 'the completion of the conversationthe operator at position Y actuates the ringing key 124,jthereby operatingrelay 29 and lighting lamp 30 as previously described in connection'with key 24, relay 129 and lamp 130. Upon the; subsequent disconnection of both link cir-; cuits from the trunk circuit all. apparatus returns to normal. 2

It will be evident that uponthe operation of relay 23or 123 in response to a toll call, not only is the corresponding slow operating relay 71-0 or provided with the local service removed from itsieflective; association with the trunkcircuit, thereby prevent.v

ing interference between the signaling Icontrol means for the different classes ofs'ervice, but also the residual *charge, retained by the associated condenser 28for' 128 is'discharged through a shunt pathfso thatit does not produce a false operation of the relay 10 or 110 when such relay isreconnected through the. trunk circuit upon the discon:

nectionfot the toll link 1 circuit from the.

trunk circuitl The relaysl0 and 110 are made slow to operate to insure the. operation of relays 23 andv 9 'orrelays fl23' and 109 prior to the operation'ofsuch slow operating relays. I p y 5 1 What is claimed is: 4f 1 V 1. In a telephone .eXehangeI. system, a plural, service trunk circuitfor reciprocal operation between two station s,v signal control means at each" station-for each service,

said. means fornditlerent services being rer H sponsive to signaling currents} of different:

' characteristics,meansfat each station forselectively impresslng currents OiiJdiflI'ereIit-HO characteristics ontthe trunl-kQ circuit to op erate the associated signal control means at; the other. station, and means operating upon theresponseiof one signal; control means to render the other signalcontrol meansthe same station unresponsiveg i 2.11] a telephone exchange i system, a

plural service; trunk circuit interconnecting.

two stations, signal control .means at one.

station. for each service,;said-means beingre; 1'20 sponsive to signaling currents ofgdifi'erent characteristics, means at the other 7 station for selectively impressing currents of ditferent characteristics on theltrunk. circuit,

a capacitance devicent the first mentioned station receiving a charge during the iinpression of the signaling current oflone characteristic, and means controlled response. of the associated signal control? means to discharge the residual charge rev tained by the device after the cessation of such impression.

3. In a telephone exchange system, a plural service trunk circuit for reciprocal operation between two stations, signal control means at each station for each service, said means for the different services being responsive to signaling currents of different characteristics, means at each station for selectively impressing currents of different characteristics on the trunk circuit to operate the associated signal control means at the other station, a capacitance device at each station receiving a charge during the impression of the signaling current of one characteristic at the other station, and means controlled by the response of the associated signal control means to discharge the residual charge retained by the device upon the cessation of such impression.

4. In a telephone exchange system, a plural service trunk circuit interconnecting two stations, signal control means at one station for each service, said means being responsive to signaling currents of different characteristics, means at the other station for selectively impressing currents of different characteristics on the trunk circuit, a capacitance device at the first mentioned station receiving a charge during the impression of signaling current of one characteristic, and means operating upon the response of the associated signal control means to simultaneously render the other signal control means unresponsive and to discharge the residual charge retained by the device after the cessation of such impression.

In Witness whereof, I hereunto subscribe my name this 2nd day of July, A. D. 1918.

CHARLES WHITE. 

